Wall securement



Nov. 12, 1963 R. D. KooNTz 3,110,064

WALL, SECUREMENT 2 sheets-sheet 1 originai Filed Aug. 2, 195'? /M/f/vm@ P05597 2 Koo/wz www/mm United States PatentY Oli ice 3,1 l @164 Patented Nov. 12, 1963 3,11,064- WALL SECUREMENT Robert D. Koontz, Manhattan Beach, Calif., assignor, by

mesne assignments, to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a corporation of Delaware Continuation of application Aug. 2, 1957, Ser. No. 675;i 988. This application Nov. 24, 1958, Ser. No. 776,109

Claims. (Ci. Ztl-4) This invention relate-s to a wall securement, and more specifically to a means -for securing together sections of Wall, having an appreciable thickness, in overlapping relationship, to form a continuous wall, capable of transmitting stress through the walls. By way of example, a sectionally formed radome, will -be illustrated.

Radomes are commonly used in airborne, shipboard and ground installations to shield the radar equipment can'ied therein, and are constructed in a manner to provide the least electromagnetic impedance to radar waves. The larger radomes are most practically constructed of a plurality of sections or segments, secured together to form a continuous wall. A practical construction of the Walls of each section is the commonly used sandwiched material, wherein a relatively -fragile cellular core is enclosed by a relatively stronger outer skin. rl'he core of such walls is preferably formed of a honeycombed, resin-irnpregnated, cloth or paper, reinforced as by an outer skin of similar material, which may be laminated to provide additional strength.

One disadvantage of radomes comprising such construction, is the diculty of obtaining a uniform electromagnetic impedance throughout its breadth, ie., both the wall section and the overlap portions should have ibstantially equal impedance to avoid distortion of the radar waves at any point thereof. In the past, it has been a common practice to strengthen the edges of each section, which are overlapped, by providing a solid laminate area of material similar to that of the skin material. Such construction may distort signals or waves passing through the radome -at this overlapped area.

A particular problem of such construction described is the transmission of stresses which exist in a radome, by virtue of the air loading on 'the radome surface, from one section to the other Without damage to the sections. These stresses actually exist in the skins of the wall. To avoid rupture of the sandwiched material, the stress should be transmitted from the inner and outer skin of one section to the inner and outer skin of the adjacent wall section.

lt is therefore among the objects of this invention to provide a new and improved Wall securement to join wall sections of the character described, Without increasing or changing the impedance to radio waves at the overlapped portion.

it is another object of this invention to provide a new and improved :wall securement which provides improved means of transmitting any existing stress -t'ro-m one wall section to theother Wall section.

It is a fur-ther object of this invention to provide a new and improved wall securement which is economical to manufacture, does not add appreciable weight to the radome, and is readily and easily installed.

A general object of this invention is to provide a new and improved wall securement -for overlapping Wall sections of a radome, which overcomes disadvantages of prior Imeans and methods heretofore intended to accomplish generally the same purpose.

These and other objects of this invention will be more apparent from the following detailed description of the drawings and appended claims.

This is a continuation of application No. 675,988, tiled August 2, 1957, and now abandoned.

ln the drawings:

FIG. l is a `View in elevation of a radome embodying this invent-ion;

FEiG. 2 is an enlarged fragmentary horizontal sec. tional view `as taken on line 2 2 of PIG. 1;

FIG. 3 is a plan view, shown partially in section, as taken substantially on a line 3 3 of FIG. 2;

FIG. 4 is an enlarged horizontal sectional View, similar to FIG. 2 illustrating another embodiment of this invention;

FIG. 5 is an enlarged horizon-tal sectional vie-W, simi-V lar to FG. 4 as taken through an overlapped portion other than the fastener of the embodiment shown in FIG. 4; and

PIG. 6 is an enlarged horizontal sectional view, similar to FIGS. 2 and 4, illustrating an overlapped portion of a radome constructed as Itaught by prior art.

Referring to the drawings, and more particularly to IFIG. 1, there is sho-Wn a radome generally referred to by the numeral 1?, having a generally hemispherical coniiguration. The radome 10 includes a plurality of arcuate-ly formed sections 11, which are arranged in overlapping relationship yto form a continuous circular or other, horizontal configuration. To facilitate assembly, the sections may -orm an opening 12 at the top of the radome which may be closed as by a cap 13. The radome has an open bottom 14.

As best seen in FIGS. 2 and 3, each section .11 comprises an inner core 16, of a layer or a plurality of layers, of a cellular `fragile material, such as the honeycombed, resin-impregnated, glass cloth or paper illustrated, or the like. To provide a uniform electromagnetic impedance throughout the entire breadth of the radome, the sections are preferably constructed so that the electrical thickness at the overlapped joint is substantially equal to the electrical thickness throughout the rest of the section. For purpose, the sections 11 are preferably formed with a double layer of lthe honeycombed, resin-impregnated, glass cloth, with the exception of the portion to be overlapped, where one of the layers is rtapered as at 17 adjacent the overlapped area, terminating in a single layer 26 of the honeycomb material at this latter area.

An outer skin 18 overlies an outer layer 19` of honeycomb material, the tapered portion =17, and an inner layer or" honeycombed material 20, and terminates at an edge 21 thereof. An intermediate skin 22 is preferably provided between the layers 19, 29 at the double-layered portion and extends over the single-layered portion -26 to lthe edge 21. The singular or laminate inner skin 23 overlies the inner surface of the inner honeycomb layer 20 and extends across fthe entire Width of the section 11, to terminate at the end 21. To strengthen and seal fthe end 21 of the section 11, an overlapping layer of skin 24 may be provided to close the edge, and preferably overlaps the inner skin 23, and the outer skin 18.

The adjacent section, designated by the numeral 11' in FIG. 2 is similarly constructed, having an inner core 1.6 of the honeycombed material described. The core 15' is formed of an outer layer `1-9, which in this section extends across .the overlap area to be joined, and an inner layer of honeycombed material Ztl which tapers as at "17', corresponding to the tapered portion 17 of the section 11. An outer skin 18', intermediate skin 2 and inner skin 23', similarly terminates at an edge 21 which is strengthened and sealed by a cap skin 24'. The skins 18, 22, 23, and 1S', 22', 23 are preferably Aformed of a resin-hnpregna-ted glass cloth which can be bonded to the cores 16, 16 respectively, by well-known bonding methods to form sections 1i, l1', having a high relative strength.

When sections l1, 11', are assembled with the narrowed portions 26, 26', respectively, in overlapping relationship, a substantially uniform electromagnetic impedance is provided `over .the radome, including the overlapped portions. If it is desired to secure more than two sections together, as in the radome il@ illustrated, each section is constructed as above described, with an edge like 21 at one end and an edge like 21' `at the other end, with complementary edges on adjacent sections.

A plurality of openings 27 are provided in the narrowed portions 26 of the section 11, extending through the inner skin 23 andthe honeycomb layer 20, and preferably terminating at the intermediate skin 22. An aligned opening 27 is provided in the corresponding narrowed portion 26' of the section 11', and extends through the outer skin 18 and honeycomb layer 19', Ito terminate skin 22. Reduced apertures 2S, 28', substantially concentric with the openings 27, 27', respectively, are provided in the laminate skin formed by the overlapping of the outer Vskin 18, intermediate skin 22, and cap skin 24, of the section 11, and the corresponding skins of the section 11'.

A pair of cup members, 31, 31', are disposed in the openings 27, 27', respectively, to clamp the overlapped portions 26, 26. The cup members 31, 3i', comprise a generally cylindrical wall 32 having an outwardly extending annular flange 29 at the outer end thereof, and a bottom 33 having an aperture 34 substantially equal to or greater than the apertures 2S, 2S'. The cup members preferably form a snug iit within the openings 27, 27', and are preferably cemented as along the inner side 36 of the :annular ange, the outer sur-face 37 of the cylindrical Wall 32, and the outer surface 38 of the bottom 33, yfor a purpose which will be further explained.

A fastener 41, having `an enlarged head 42 and a threaded shank 43 is disposed with the head 42 within the cup member 31. The shank 43 extends through the aligned apertures 28, 28 iand 34, and into the cup member 31', where it is secured as by a threaded nut 44, to clamp the bottoms 33 of the cup members 31, 31' together, with the laminate inner skin of the section 111 and the laminate outer skin of the section 11 therebetween.

Under load, high stresses may be imparted to the inner and outer skinsof the radome section. Such stresses must be transmitted from one section `to another without injury to the overlapped joint therebetween. A very satisfactory transmission of the stresses is accomplished in the instant invention, by the provision of the cup members which securely fasten the overlapped portions together, and additionally, by fthe cemented surfaces previously mentioned, which transmit the stresses.

The stress in the skin 23 is transmitted to the undersurface of the cup flange 29 of the cup member 31, carried by the cement thereon, transmitted along the ceented joint between the cup .cylinder wall 32 and the opening 27, to the undersurface 38 of the bottom 33, to the laminate portion 15, frictionally to the laminate portion 25, and thence to the inner skin 23 of the section 111. The stress in the outer skin y18 of the section 11, is similarly transmitted to the outer skin 18' of the section 11', through theV laminate section 15, the laminate section 25, cemented undersurface 38 of the cup member 31, cemented surface 37 of the wall 32, the cemented inner surface 35 of the -ange 29, to .the skin 18' of the section 11. Therefore, the stress loads are uniformly transmitted throughout the body of the radome 10, to provide a very strong, yet lightweight body which is `capable of passing radar waves at a substantially uniform impedance. The area covered by the cup member 31, 31', is very small relative to the wide expanse of the radome, and the differing impedance at the points where such cup members are applied is usually of little or no consequence in the radiation pattern of the antenna Within the radome.

The overall height of the cup members 31, 31' is preferably of such dimension that when the lbottoms 33 are clamped tightly by the fastener 41, the flanges 29 tightly grip the outer skins 18 and the inner skin 23, avoiding excessive distortion of the core material at these points by the compression.

Referring to FIGS. 4 and 5, another embodiment of this invention is illustrated, wherein the inner core 51 of a vwall section 5@ `comprises a single layer of honeycombed, resin-impregnated, glass cloth, which is tapered as at 52 to form a relatively thinner overlapping portion 53. The adjoining section 56' is similarly `constructed with a corresponding tapered inner core 51 to vprovide a relatively thinner overlapping portion 54.

Openings 56, 57 are provided in the sections 53, 54, respectively, similar to the openings 27, 27 of the sections i, dit',A respectively, to accommodate cup members 5S, 59, similar to the cup members 31, 31'. A fastener 61 extends through the apertures 62 of the cup members 5S, 59, and iis secured as by a threaded nut 63 to clamp the bottoms 164 of the cup members.

lf desired, a strip 66 of resilient material, such as rubber, neoprene, plastics or the like, may be interposed between the overlapped portions of the sections Si?, 50', to provide a watertight seal at this overlapped portion. The construction of the sections shown in FlGS. 4 and 5, Vis very similar to that of the construction shown in PIG. 2, inasmuch as the electromagnetic impedance is uniform throughout the body. As best seen in FIG. 5, wherein a cross-section is shown at a point other than where the cup members are installed, the combined thickness of the overlapped skins -is substantially the same as the slain proper at a point spaced from the edge.

-ln the instant embodiment, the stresses are transmitted at each ycup location by a cement coating, applied as previously described, and by the clamping of the cups.

ln EEG. 6, wall sections 70 and 70' illustrate a conventional method taught by prior art. lt has been the practice to provide an inner core 71 of honeycomb resinimpregnated glass cloth, lost-wax channels forming similar construction, or the like, wherein the overlapped portions 72, 73 of the sections 79, 70 respectively, are formed by providing a solid laminate construction in this portion. Such laminate portions have heretofore included a plurality of layers of resin-impregnated, glass cloth similar to the skin material, or identical thereto. TheA impedance to passage of radio waves is vrvery `different at this overlapped portion than throughout the remaining area of the sections. This has been unsatisfactory, since the difference in electromagnetic impedance `causes a .considerable `distortion in the external radiation pattern of the radar antenna within the radome. Although the stress transmission has been, by this method, adequate, the poor antenna pattern has been a great disadvantage.

In general, this invention provides a radome which can be economically manufactured, which can be made in sections to facilitate assembly and manufacture thereof and which has a desired substantially uniform electromagnetic impedance throughout its breadth. Cup members are provided to clamp adjacent sections together at the overlapped areas in such a manner that the sections are held securely together, yet are highly capable of transmitting stress from one Vsection to the other.

While the instant invent-ion has been shown and described herein in what is conceived to be the most practical and preferred embodiments, it is recognized that departure may be made therefrom within the scope of the invention, which is therefore not to be `limited to the details disclosed herein, but is to be accorded the full scope of the claims.

What l claim as new and desire to secure by Letters Patent is:

1. A wall securement comprising: a pair of overlapping walls having an appreciable thickness and being made of a relatively fragile cellular body enclosed by a relatively stronger outer skin, said walls having enlarged openings, intermediate of the overlap, extending through the outer surface skin thereof and said fragile body, and having reduced openings extending through adjacent inner surfaces, a pair of lflanged cup members having apertured bottoms, and fastening means extending through said openings and having enlarged portions in said cup members yfor clamping the walls together in overlapping relationship.

2. A wall securement in accordance with claim 1 lwherein said cup members are cemented in said enlarged openings for transmitting stress from one skin of one of ysaid walls to the clamped area, and from the :clamped area to the corresponding skin of the other said walls.

3. A wall securement comprising: a pair of overlapping Walls having an appreciable thickness and being made of a relatively fragile cellular body enclosed by a relatively stronger skin, a pair of anged cup members disposed in openings of said walls, said cup members having -apertured bottoms, and fastening means extending through said apertures for clamping said walls in overlapping relationship.

4. A wall securement in accordance with claim 3 wherein said cup members are combined to said walls for transmitting stress from one skin to one of said walls to the clamp area, and from the clamped area to the corresponding skin of the other of said walls.

5. A wall securement in accordance with claim 4 wherein a portion of the skin of each lwall is clamped between said apertured bottoms.

y6. A wall securement in accordance with claim 5 including resilient gasket means disposed between said walls at the overlapped region.

7. A wall securement comprising a pair of overlapping Walls having an appreciable thickness and being made of a relatively fragile cellular body enclosed by a relatively stronger outer skin, said walls having enlarged openings, intermediate of the overlap, extending through the outer surface skin thereof and said fragile body, and having reduced opening extending through adjacent inner surfaces, a pair of hanged cup members having apertured bottoms, land fastening means extending through said openings and having enlarged portions in said cup members for clamping the ywall together in overlapping relationship, the overlapped portions of said walls having substantially the `same impedance, to the passage through the walls of electromagnetic radiations, as the remaining portions of said walls.

8. A wall securement comprising a pair of overlapping Walls having an appreciable thickness and being made of a relatively fragile cellular body enclosed by a relatively stronger skin, a pair of cup members having annular flanges and apertured bottoms disposed in aligned openings of said walls whereby said flanges engage outer surfaces of said Walls and `said bottoms are in face to face relationship; fastening means extending through said yapertured bottoms for clamping said walls in overlapping relationship whereby said walls are clamped between said flanges; means for transmitting stress from one skin of one said walls to the clamped area, and from the clamped area to the corresponding skin of Ithe other of said Walls, the overlapped portion of said walls having substantially the same impedance to the passage through the Walls of electromagnetic radiations, as the remaining por-tions of the walls.

9. A radome comprising: a plurality of wall sections, each section having an appreciable thickness and having a relatively fragile cellular body enclosed by relatively stronger outer skins; peripheral edges of reduced thickness on each of said sections, said edges of one of said sections being in overlapped relationship -wi-th said edge of an `adjacent section, the overlapped portion of said sections having substantially the same impedance to the passage through the walls of electromagnetic radiations as the remaining portion of said walls; and securement means extend-ing through said overlapped portions for securing said sections, a pair of flanged cup members disposed in openings of said walls in said overlapped edge portions, said cup members having apertured bottoms, and said securement means comprising -a fastening member extending through said apertures for clamping said walls in overlapping relationship.

10. The securement of claim 9 wherein said wall sections have enlarged openings extending through the outer surface skin and the said fragile body to receive the said `cup members and reduced openings extending through adjacent inner surfaces to receive the said fastener member.

References Cited in the le of this patent UNITED STATES PATENTS 2,295,248 Wittner Sept. 8, 1942 2,501,072 McMillan et al Mar. 21, 1950 2,727,286 Moore Dec. 20, 1955 2,854,668 McMillan et al Sept. 30, 1958 2,887,740 Potchen May 26, 1959 

3. A WALL SECUREMENT COMPRISING: A PAIR OF OVERLAPPING WALLS HAVING AN APPRECIABLE THICKNESS AND BEING MADE OF A RELATIVELY FRAGILE CELLULAR BODY ENCLOSED BY A RELATIVELY STRONGER SKIN, A PAIR OF FLANGED CUP MEMBERS DISPOSED IN OPENINGS OF SAID WALLS, SAID CUP MEMBERS HAVING APERTURED BOTTOMS, AND FASTENING MEANS EXTENDING THROUGH SAID APERTURES FOR CLAMPING SAID WALLS IN OVERLAPPING RELATIONSHIP. 